Heat-treating furnace



Feb.' 26, 1935. W; E, BLYTHE; 1,992,467

` HEAT TREATING FURNAGE Original Filed May l2, 1933 5 Sheets-Sheet 3Patented Feb. 26, 1935 UNITED STATES HEAT-TREATING FURNACE William E.Blythe, Birmingham, Mich., assigner to Driver-Harris Company, Harrison,N. J., a corporation of New Jersey Application May 12, 1933,seria1No.s7o,649 Renewed July 11, 1934 9 Claims.

My invention relatesto high temperature heat treating furnaces of thetype in which material to be treated is conveyed through the furnace onrolls and comprises an improved furnace of this character.

An object of the invention is to improve the construction and operationof the now existing furnaces of this type by substituting thereinconveyor rolls of improved construction for the water cooled steelconveyor rolls now in common use whileutilizing without substantialmodification much of the present expensive equipment of the furnace.

Another object of the invention is to provide in newly constructed or inexisting furnaces improved conveyor rolls of relatively small diameteradapted to withstand the intense heat of the furnace, and to providesupporting means therefor which will insure that the rolls run true.

The several features of the invention whereby the above-mentioned andother objects of the invention may be obtained, will be readilyunderstood from the following description and accompanying drawings, inwhich:

Fig. 1 is a transverse sectional view, partly in elevation, of a portionof a furnace embodying the features of my invention in their preferredform;

Fig. 2 is a. detail sectional view on an enlarged scale taken along theline 2-2 of Fig. 1;

Fig. 3 is a transverse sectional view, partly in elevation, of a portionof a furnace illustrating a modification of the invention;

Fig. 4 is a detail sectional view, on an enlarged scale, taken along theline 4-4 of Fig. 3; and

Fig. 5 is atransverse sectional view, partly in elevation of a portionof a furnace illustrating still another embodiment of the invention.

The furnace illustrated in the drawings is of the type of the onedescribed and claimed in my Patent No. 1,843,440, dated February 2,1932, and pending application Serial No. 653,656, filed Jan. 26, 1933.This furnace is provided with a,

furnace chamber having side walls 2, a top wall 4 and a bottom wall 6and conveyor rolls-extending transversely of the furnace chamber. Eachconveyor roll may comprise a hollow shaft 8 and, if desired, materialconveying disks 10 secured thereon. The disks 10 of the several rollsare preferably arranged in staggered relation so as to permit each diskto extend into the space between adjacent disks of adjacent rolls.

In theembodiments of the invention illustrated in Figs. 1 to 4 inclusiveeach conveyor roll 8 is supported by a pair of bearing rollers 12positioned within the furnace chamber at a point substantially midway ofthe length of the conveyor roll. The pair of bearing rollers 12 aremounted in a recess on a support or cradle 14 secured to a stool orpedestal 16 by bolts 18. Preferably each bearing roller 12 is providedwith an annular cored out recess 20 to receive projections on thesupport 14 to prevent the bearing roller from working out of the bearingrecess in the support. The support 14 is made in two sections that arearranged in opposed relation to permit the bear-v ing rollers to beeasily assembled therein. A hood 22 that may also be made in twosections extends over each conveyor roll and has its ends secured, as bypinning or welding, to the sections of support 14. This hood preventsdirt and scale from getting on the bearing rollers, and also ensuresagainst the conveyor roll working off of the bearing rollers.

Each pedestal 16 extends downwardly through the bottom of the furnacechamber and has its lower end supported on a steel I-beam 24 whichextends transversely of the furnace.

The conveyor rolls 8, bearing rollers 12, supports 14 and pedestals 16all may be made of nickel-chromium-iron or other suitable heat resistingalloy.

In the embodiment of the invention illustrated in Fig. 1 each conveyorroll 8 extends substantially the width of the furnace chamber, and iscoupled by means of suitable flexible couplings 26 of heat resistantalloy between sections 28 and 30 of a hollow steel driving shaft; theends of the sections 28 and 30 to which the roll 8 is coupled extendingthrough aligned openings 32 in the side walls 2 of the furnace andthrough suitable stuffing boxes 34 mounted on the outer walls of thefurnace. Each section of the steel drive shaft is hollow and is watercooled as by a valve controlled pipe 36 connected at one end with awater main 38 and extending ,axially through the shaft section to apoint adjacent the coupling 26. The shaft sections 28 and 30 aresupported in fixed bearings 40 positioned outside of the furnacechamber. A main drive shaft 42 drives the steel drive shaft sections andconveyor rolls through-bevel gears 44'.

By embedding the lower portions of the pedestals 16 in the masonry ofthe bottom or base 6 of the furnace, and mounting them on steel supportswell protected from the heat of the furnace as above described, they arerigidly held and effectively stand up under the weight of the conveyorrolls and work.

In order to compensate for growth in the diameters of the conveyorrolls, to insure proper engagement of the bearing rollers with theconveyor rolls and to maintain the rolls level, the bearing rollers areadapted to be adjusted vertically and this may be done during operationof the furnace. To provide for this, the bottom of each pedestal restsupon a wedge member 46 that is adapted to be moved in oppositedirections to raise and lowerthe pedestal, by means of a shaft 48 thathas one end connected by a swivel joint with said wedge member. Saidshaft has screw-thread engagement with a fixed member 50 andextendsoutside of the furnace to be turned by a hand-crank 52.

From the above description of the construction illustrated in Figs. 1and 2 it will be apparent that the provision of the central bearingsupport for each conveyor roll within the furnace chamber together with.the flexible couplings to the steel drive shaft sections gives adequatesupport for the conveyor roll and permits the use of rolls of relativelysmall diameter because but a relatively short span between points ofsupport is exposed to the intense heat of the furnace. The provision foradjustment of the bearing support for the conveyor roll insures propersupport for the roll even after growth. Moreover, these advantages maybe obtained without extended modication of equipment in existingfurnaces. 'I'his is true because with the construction illustrated, themain drive shaft 42, bearings 40, and water supply system are all partsof standard equipment used with furnaces having water cooled conveyorrolls and the drive shaft sections 30 and 32 may be parts of extensionsof such a conveyor roll from which the central section has been removed.'I'hus the only new parts necessary to obtain the improved operationpossible with the present construction are the couplings 26, conveyorrolls 8, bearing rollers 12 and the supporting means therefor.

Certain of the advantages of the sectional construction of the conveyorrolls or roll shafts illustrated in Figs. 1 and 2 may be obtained andelimination of Water cooling may be effected in some instances, if thesteel drive shaft sections and coupling thereto are replaced, asindicated in Fig. 3, by shaft extensions 54 integral with the conveyorrolls 8, the extensions 54 passing through the openings 32 in the endwalls of the furnace and through the stuffing boxes 34 and beingsupported at their ends by fixed bearings 56 outside the furnacechamber.

Drive shaft 42 may be geared directly to one extension 54 by piniongears 58 to drive the conveyor roll or, if desired, an intermediatesection of steel shafting may be coupled to the extension 54 and drivenby the gears 58. Conveyor rolls 8 are supported adjacent their center bybearing rollers 12 carried by support 14 and adjustable pedestal 16 asin the construction of Fig. l. With the arrangement illustrated in Figs.3 and 4, flexible couplings of heat iesistant alloys are not requirednor is water cooling of any part necessary.

In each embodiment of the invention so far described a central bearingsupport for each conveyor roll is illustrated. In relatively narrowfurnace chambers this central bearing support may be omitted and therelatively shorter conveyor rolls supported at their ends only. Such anarrangement is illustrated in Fig. 5 wherein the only support for theconveyor rolls 8 coinprises the exible couplings 26 which, as in Fig.

1, couple the conveyor rolls between water cooled sections 28 and 30 ofa steel driving shaft.

The following is claimed:

1. In a heat treating furnace of the class described, the combination ofa furnace chamber having side walls withaligned openings therein,conveyor rolls within the chambery in alignment with the openings in theside walls, shafts extending through said openings, exible couplingsconnecting the ends of said rolls to said shafts, and bearings for saidshafts positioned outside the furnace chamber.

2. A structure according to claim 1 in which said shafts are cooled bythe circulation of a cooling fluid therethrough.

3. In a heat treating furnace of the class described, the combination ofa furnace chamber having side walls, conveyor rolls extending across thefurnace chamber, each roll having shaft extensions projecting throughopenings in the side walls, bearings for said shaft extensions arrangedoutside of the furnace chamber, a bearing for an intermediate portion ofthe roll arranged within the furnace, and means for adjusting said lastmentioned bearing vertically during the operation of the furnace.

4. In a heat treating furnace of the class described, the combination ofa furnace chamber having side Walls with pairs of aligned openingstherein, conveyor rolls within the chamber in alignment with theopenings in the side walls, shafts connected with said rolls andextending through said openings, bearings for said shafts positionedoutside the furnace chamber, a bearing support for each roll positionedwithin the furnace substantially midway between the side walls, andmeans for driving said conveyor rolls and shafts.

5. The combination according to claim 4 wherein said shafts and rollsare iiexibly coupled together within the furnace chamber adjacent theside walls, and wherein means are provided for water cooling saidshafts. said rolls being of heat resistant alloy and said shafts beingof steel.

6. The combination according to claim 4 wherein said shafts are integralwith said rolls and form extensions thereof of relatively smallerdiameter, said rolls and shafts being of heat resistant alloy.

7. In a heat treating furnace of the class described, the combination ofa furnace chamber having side ^walls, conveyor rolls extending betweenthe side walls, a bearing support for each roll positioned within thefurnace and spaced a distance from the side Walls, means accessiblewithout the furnace chamber for adjusting said supports to compensatefor growth of the rolls, means outside of the furnace chamber forsupporting the ends of each of said rolls, and means outside of saidchamber for driving said rolls.

8. The combination according to claim '7 wherein the side walls of saidfurnace have openings therein in alignment with said rolls and whereinthe means for supporting the ends of said rolls include shafts flexiblycoupled to said rolls Within the furnace adjacent the side walls thereofand extending through said openings, said shafts being supportedexternally of the furnace and being driven by said driving-means.

9. The combination according to claim '7 wherein the side walls of saidfurnace chamber have openings therein in alignment with said rolls, saidrolls having extensions passing through said openings and wherein saidmeans for supporting the ends of said rolls comprise -lxed bearings forsaid extensions positioned outside of the furnace chamber. i

WILLIAM E. BLYTHE.

